Containers Vs. Virtual Machines: Why Containers are More Popular

Imagine a ship carrying cars wrapped with different layers of packaging materials. Now imagine that same ship, but the cars are not wrapped and are just stacked on top of each other. Which ship would be more efficient?

The answer is obvious: The ship carrying the packaged cars. This is the same idea when it comes to software containers. That’s because containers are a more efficient way to package and transport goods, so the “cars” (as used in this example) are less likely to be damaged during transit.

Containers and virtual machines (VMs) are both ways to package software so it can be run in different environments. But while VMs virtualize the underlying software, containers virtualize the operating system, meaning each container can only hold one application and its libraries.

Containerization makes it more efficient for a DevOps platform like Docker to keep its applications better organized. If each application were packaged in its own VM, the host operating system would need to manage and allocate resources for each VM. This would be a very inefficient way to run multiple applications on a single server.

With containers, on the other hand, the host operating system only needs to manage and allocate resources for the containers as a whole. This makes running multiple applications on a single server much easier and results in better performance overall.

If you’re new to the concept of containers, all this can seem pretty overwhelming. To help you out, we’ve put together this guide discussing the similarities and differences between containers and VMs, and why containers are becoming more popular.

What Are Containers?

As mentioned before, containers are a way to package software so it can be easily deployed and run in different environments. Think of it as a type of distributed database to store electronic data, similar to blockchain technology. 

A container image is software that comes with everything it needs to run an application, including the code, runtime, libraries, environment variables and configuration files. Containers are isolated from each other and share the host operating system kernel, which makes them much more lightweight than VMs.

What Are Virtual Machines?

Virtual machines (VMs) are a way to run multiple operating systems (OSes) on a single physical server. Each VM has its own complete copy of an operating system, including the kernel and its own virtual hardware resources.

VMs are very resource-intensive and can be pretty slow. They’re also much more complex to set up and manage than containers. For example, if you wanted to run two different versions of Linux on a single server, you would need to set up two VMs. This would require twice the amount of disk space and RAM, and you would need to manage and update both VMs separately.

With containers, on the other hand, you could easily run both versions of Linux on the same server, which would be much more efficient in terms of resources and easier to manage.

Why Are Containers Becoming More Popular Than VMs?

Developers are typically creatures of habit. They like things to be a certain way and are often reluctant to change, which is why VMs have been the go-to choice for many years. But as container technology has matured, it’s become clear that containers have several advantages over VMs.

Containers are More Efficient

Containers are ideal for running multiple applications on a single server. In fact, you can run thousands of containers on one server without any noticeable impact on performance. That’s because containers share the host operating system kernel so they don’t need to virtualize the hardware like VMs.

Containers are Portable

Another significant advantage of containers is that they’re portable—you can easily move them from one environment to another without worrying about compatibility issues. This is a huge advantage over VMs, which are often difficult to move between different environments. Portability also makes it easier to work with clients using different operating systems.

Containers are Easy to Use

Containers are also much easier to use than VMs because they’re self-contained and include everything you need to run an application. From a developer’s perspective, this means you can simply write your code and package it into a container image. Then you can deploy that image to any server or cloud environment and it will just work.

Many companies, such as Amazon, Google and Microsoft, offer container services that make it even easier to use containers. For example, Amazon’s Elastic Container Service (ECS) allows you to run containers in the AWS cloud with just a few clicks.

Containers are Flexible

Another advantage of containers is that they’re very flexible. You can use them for both development and production environments.

Let’s say you have a web application that you want to deploy to production. You can easily package the application into a container image and deploy it to a container service such as Amazon ECS. But what if you need to make some changes to the application? With containers, you can rebuild the image with your changes and redeploy it. This is a lot faster and easier than redeploying a VM.

What are the Trade-Offs?

There are always trade-offs, but there are also many things we can do to mitigate them. The most significant trade-off with containers is that they can be less secure than VMs if they’re not correctly configured. That’s because containers share the kernel of the host operating system and have access to all of the host’s resources. Imagine if a malicious container could access the host’s file system; it could wreak havoc on the entire system.

Fortunately, there are several ways to mitigate this risk. For example, you can use a DevOps management platform such as Docker Swarm or Kubernetes, which allows you to deploy your containers securely. So, overall, there’s not much to worry about when it comes to security, and it also ensures good digital citizenship among your employees.

Are VMs Obsolete?

Both containers and VMs have their advantages and disadvantages. In many cases, it makes sense to use both technologies side-by-side. In fact, I would argue that VMs and containers complement each other very well.

VMs are great for running legacy applications that were designed to run on a specific operating system. For example, you may have an application designed to run on Windows Server 2008. If so, it would be challenging to containerize the application and get it to run on a newer version of Windows or Linux. In this case, you would be better off running the application in a VM to keep it isolated from other applications and ensure that it will continue working as expected.

At the same time, you can use containers for your newer applications. This will allow you to take advantage of the benefits of containers, such as portability, ease of use and flexibility.

That being said, there are definitely cases where it makes sense to use one technology over the other. But, as time goes on, we believe containers will become the go-to solution for businesses that want to adopt DevOps for all things related to application deployment, management, etc.

Final Thoughts

Containers have undoubtedly risen in popularity over the past few years, and it doesn’t seem like that trend will change anytime soon. While VMs will always have their place, containers offer many benefits that make them a more appealing choice for companies looking to modernize their application development and deployment processes.

We hope this article has given you a better understanding of containers, VMs, and their key differences. With the information provided, you should be able to make an informed decision on which technology is right for your project.

Nahla Davies

Nahla Davies is a technical copywriter and former software specialist and lead programmer at several major technology companies whose clients include Collibra, UpGuard and Netflix. Since 2015 Davies has worked with enterprise clients around the world developing RegTech protocols and best practices. She worked both enterprise side and with sovereign governments acting as a key contributor for notable public projects like DCOM. Since 2020 Davies has taken a less active role in compliance consulting and started sharing my insights as a technical copywriter. Visit to learn more.

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